Cannulae used in endoscopic retrograde cholangiopancreatography (ERCP) allow access to the bile or pancreatic ducts through the sphincter of Oddi which opens into the duodenum at the papilla of Vater. When performing an ERCP procedure, difficulty is sometimes encountered in the attempt to successfully cannulate the desired duct within this ductal system. This difficulty can result in a prolongation of the procedure or possibly inadequate diagnosis and/or therapy, which can possibly cause severe and sometimes life-threatening consequences.
Previous devices designed to facilitate selective access of the segments within the biliary tree have included steerable catheters, bowed papillotomes, and curved tip wire guides. None of these devices have satisfactorily provided precise control of the cannula tip and therefore have proven inadequate for selective cannulation. Fully steerable cannulas have not enjoyed wide acceptance because they are too bulky for practical operation through the biopsy channel of a pancreaticobiliary endoscope. Thinner steerable devices, which are capable of steering in only one or two directions, offer little advantages over a standard catheter.
Bowed papillotomes are sometimes used like a standard catheter to gain access to specific structures within the biliary ductal system. When used in this manner, however, the cutting wire of the bowed papillotome interferes with the cannulation process, while the only advantage over a standard catheter that is provided is additional flexion for redirecting the tip in only one direction. As a result, bowed papillotomes are awkward to use and fail to provide improved effectiveness.
Commonly used to gain access to many structures within the body, wire guides are also commonly used to effect cannulation of ducts within the biliary ductal system. Guide wires, however, carry the risk of blunt trauma to structured segments of the bile or pancreatic ducts which can result in life-threatening infection, perforation or pancreatitis. Given the present alternatives, there is a need and usefulness for a new approach which extends the utility of endoscopic cannulas that are used to secure selective intraluminal access to hollow tubular structures, such as are found in the pancreaticobiliary tree.